The air comes in and goes out like someone passing through a swinging door. If you think, ”I breathe”, the ”I” is extra. There is no you to say ”I”. What we call ”I” is just a swinging door, which moves when we inhale and when we exhale. It just moves; that is all. When your mind is pure and calm enough to follow this movement, there is nothing: no ”I”, no world, no mind nor body.